Operating system customization in an on-demand network code execution system

ABSTRACT

Systems and methods are described for managing operating system customization in an on-demand code execution system in a manner that enables efficient execution of code. A user may generate a task on the system by submitting code. The system may determine the operating system functions that the submitted code may invoke when executed on the system, and may determine whether the required functionality can be provided by a customized operating system. The customized operating system may provide some functionality but omit other functionality, and thereby avoid consuming any resources associated with making the omitted functionality available. For example, the system may determine that the user-submitted code does not require filesystem interactions, network interactions, interactions with particular devices, caching, paging, profiling, etc., and may thus provide an operating system that does not include one or more of these services.

BACKGROUND

Computing devices can utilize communication networks to exchange data. Companies and organizations operate computer networks that interconnect a number of computing devices to support operations or to provide services to third parties. The computing systems can be located in a single geographic location or located in multiple, distinct geographic locations (e.g., interconnected via private or public communication networks). Specifically, data centers or data processing centers, herein generally referred to as a “data center,” may include a number of interconnected computing systems to provide computing resources to users of the data center. The data centers may be private data centers operated on behalf of an organization or public data centers operated on behalf, or for the benefit of, the general public.

To facilitate increased utilization of data center resources, virtualization technologies allow a single physical computing device to host one or more instances of virtual machines that appear and operate as independent computing devices to users of a data center. With virtualization, the single physical computing device can create, maintain, delete, or otherwise manage virtual machines in a dynamic manner. In turn, users can request computer resources from a data center, including single computing devices or a configuration of networked computing devices, and be provided with varying numbers of virtual machine resources.

In some scenarios, virtual machine instances may be configured according to a number of virtual machine instance types to provide specific functionality. For example, various computing devices may be associated with different combinations of operating systems or operating system configurations, virtualized hardware resources and software applications to enable a computing device to provide different desired functionalities, or to provide similar functionalities more efficiently. These virtual machine instance type configurations are often contained within a device image, which includes static data containing the software (e.g., the OS and applications together with their configuration and data files, etc.) that the virtual machine will run once started. The device image is typically stored on the disk used to create or initialize the instance. Thus, a computing device may process the device image in order to implement the desired software configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram depicting an illustrative environment in which an on-demand code execution system can operate to execute tasks corresponding to code, which may be submitted by users of the on-demand code execution system, and to enable customization of virtual machine operating systems to facilitate execution of the submitted code;

FIG. 2 depicts a general architecture of a computing device providing a OS customization system that is configured to facilitate customization of OSes used to facilitate execution of tasks on the on-demand code execution system of FIG. 1;

FIG. 3 is a flow diagram depicting illustrative interactions for submitting code corresponding to a task to the on-demand code execution system of FIG. 1, and for the on-demand code execution system to provide a customized operating system to facilitate execution of the task on the on-demand code execution system;

FIG. 4 is a flow diagram depicting illustrative interactions for executing a task utilizing the customized operating system provided on the on-demand code execution system of FIG. 1;

FIG. 5 is a flow diagram depicting illustrative interactions for modifying customized operating systems on the on-demand code execution system of FIG. 1 based on analysis of an executing task on the on-demand code execution system of FIG. 1;

FIG. 6 is an illustrative visualization of customized operating systems that may be generated or selected to facilitate execution of tasks on the on-demand code execution system of FIG. 1; and

FIG. 7 is a flow chart depicting an illustrative routine for determining an OS configuration to facilitate execution of tasks on the on-demand code execution system of FIG. 1.

DETAILED DESCRIPTION

Generally described, aspects of the present disclosure relate to an on-demand code execution system. The on-demand code execution system enables rapid execution of code, which may be supplied by users of the on-demand code execution system. More specifically, embodiments of the present disclosure relate to customizing virtual machine operating systems to facilitate rapid execution of code in the on-demand code execution system. As described in detail herein, the on-demand code execution system may provide a network-accessible service enabling users to submit or designate computer-executable code to be executed by virtual machine instances on the on-demand code execution system. Each set of code on the on-demand code execution system may define a “task,” and implement specific functionality corresponding to that task when executed on a virtual machine instance of the on-demand code execution system. Individual implementations of the task on the on-demand code execution system may be referred to as an “execution” of the task (or a “task execution”). The on-demand code execution system can further enable users to trigger execution of a task based on a variety of potential events, such as detecting new data at a network-based storage system, transmission of an application programming interface (“API”) call to the on-demand code execution system, or transmission of a specially formatted hypertext transport protocol (“HTTP”) packet to the on-demand code execution system. Thus, users may utilize the on-demand code execution system to execute any specified executable code “on-demand,” without requiring configuration or maintenance of the underlying hardware or infrastructure on which the code is executed. Further, the on-demand code execution system may be configured to execute tasks in a rapid manner (e.g., in under 100 milliseconds [ms]), thus enabling execution of tasks in “real-time” (e.g., with little or no perceptible delay to an end user).

The on-demand code execution system may instantiate virtual machine instances to execute the specified tasks on demand. The virtual machine instances may be provisioned with operating systems, which provide functionality that the user-specified executable code may require during execution. For example, an operating system may provide functions such as task scheduling, filesystem management, memory management, caching, profiling, networking, hardware device drivers, and the like. In some instances, the time required to instantiate a virtual machine instance and provision it with an operating system may be significant relative to the overall time required to execute the task.

As will be appreciated by one of skill in the art in light of the present disclosure, the embodiments disclosed herein improves the ability of computing systems, such as on-demand code execution systems, to execute code in an efficient manner. Moreover, the presently disclosed embodiments address technical problems inherent within computing systems; specifically, the limited nature of computing resources with which to execute code, the resource overhead associated with provisioning virtual machines with operating systems to facilitate code execution, and the inefficiencies caused by provisioning functionality that is not utilized. These technical problems are addressed by the various technical solutions described herein, including the provisioning of an execution environment with a customized operating system based on the functionality required by the code to be executed. Thus, the present disclosure represents an improvement on existing data processing systems and computing systems in general.

The on-demand code execution system may include a virtual machine instance manager configured to receive user code (threads, programs, etc., composed in any of a variety of programming languages) and execute the code in a highly scalable, low latency manner, without requiring user configuration of a virtual machine instance. Specifically, the virtual machine instance manager can, prior to receiving the user code and prior to receiving any information from a user regarding any particular virtual machine instance configuration, create and configure virtual machine instances according to a predetermined set of configurations, each corresponding to any one or more of a variety of run-time environments. Thereafter, the virtual machine instance manager receives user-initiated requests to execute code, and identifies a pre-configured virtual machine instance to execute the code based on configuration information associated with the request. The virtual machine instance manager can further allocate the identified virtual machine instance to execute the user's code at least partly by creating and configuring containers inside the allocated virtual machine instance, and provisioning the containers with code of the task as well as an dependency code objects. Various embodiments for implementing a virtual machine instance manager and executing user code on virtual machine instances is described in more detail in U.S. Pat. No. 9,323,556, entitled “PROGRAMMATIC EVENT DETECTION AND MESSAGE GENERATION FOR REQUESTS TO EXECUTE PROGRAM CODE,” and filed Sep. 30, 2014 (the “'556 patent”), the entirety of which is hereby incorporated by reference.

As used herein, the term “virtual machine instance” is intended to refer to an execution of software or other executable code that emulates hardware to provide an environment or platform on which software may execute (an “execution environment”). Virtual machine instances are generally executed by hardware devices, which may differ from the physical hardware emulated by the virtual machine instance. For example, a virtual machine may emulate a first type of processor and memory while being executed on a second type of processor and memory. Thus, virtual machines can be utilized to execute software intended for a first execution environment (e.g., a first operating system) on a physical device that is executing a second execution environment (e.g., a second operating system). In some instances, hardware emulated by a virtual machine instance may be the same or similar to hardware of an underlying device. For example, a device with a first type of processor may implement a plurality of virtual machine instances, each emulating an instance of that first type of processor. Thus, virtual machine instances can be used to divide a device into a number of logical sub-devices (each referred to as a “virtual machine instance”). While virtual machine instances can generally provide a level of abstraction away from the hardware of an underlying physical device, this abstraction is not required. For example, assume a device implements a plurality of virtual machine instances, each of which emulate hardware identical to that provided by the device. Under such a scenario, each virtual machine instance may allow a software application to execute code on the underlying hardware without translation, while maintaining a logical separation between software applications running on other virtual machine instances. This process, which is generally referred to as “native execution,” may be utilized to increase the speed or performance of virtual machine instances. Other techniques that allow direct utilization of underlying hardware, such as hardware pass-through techniques, may be used, as well.

While a virtual machine executing an operating system is described herein as one example of an execution environment, other execution environments are also possible. For example, tasks or other processes may be executed within a software “container,” which provides a runtime environment without itself providing virtualization of hardware. Containers may be implemented within virtual machines to provide additional security, or may be run outside of a virtual machine instance.

The foregoing aspects and many of the attendant advantages of this disclosure will become more readily appreciated as the same become better understood by reference to the following description, when taken in conjunction with the accompanying drawings.

FIG. 1 is a block diagram of an illustrative operating environment 100 in which an on-demand code execution system 110 may operate based on communication with user computing devices 102, auxiliary services 106, and network-based data storage services 108. By way of illustration, various example user computing devices 102 are shown in communication with the on-demand code execution system 110, including a desktop computer, laptop, and a mobile phone. In general, the user computing devices 102 can be any computing device such as a desktop, laptop or tablet computer, personal computer, wearable computer, server, personal digital assistant (PDA), hybrid PDA/mobile phone, mobile phone, electronic book reader, set-top box, voice command device, camera, digital media player, and the like. The on-demand code execution system 110 may provide the user computing devices 102 with one or more user interfaces, command-line interfaces (CLIs), application programing interfaces (APIs), and/or other programmatic interfaces for generating and uploading user-executable code (e.g., including metadata identifying dependency code objects for the uploaded code), invoking the user-provided code (e.g., submitting a request to execute the user codes on the on-demand code execution system 110), scheduling event-based jobs or timed jobs, tracking the user-provided code, and/or viewing other logging or monitoring information related to their requests and/or user codes. Although one or more embodiments may be described herein as using a user interface, it should be appreciated that such embodiments may, additionally or alternatively, use any CLIs, APIs, or other programmatic interfaces.

The illustrative environment 100 further includes one or more auxiliary services 106, which can interact with the one-demand code execution environment 110 to implement desired functionality on behalf of a user. Auxiliary services 106 can correspond to network-connected computing devices, such as servers, which generate data accessible to the one-demand code execution environment 110 or otherwise communicate to the one-demand code execution environment 110. For example, the auxiliary services 106 can include web services (e.g., associated with the user computing devices 102, with the on-demand code execution system 110, or with third parties), databases, really simple syndication (“RSS”) readers, social networking sites, or any other source of network-accessible service or data source. In some instances, auxiliary services 106 may be associated with the on-demand code execution system 110, e.g., to provide billing or logging services to the on-demand code execution system 110. In some instances, auxiliary services 106 actively transmit information, such as API calls or other task-triggering information, to the on-demand code execution system 110. In other instances, auxiliary services 106 may be passive, such that data is made available for access by the on-demand code execution system 110. For example, components of the on-demand code execution system 110 may periodically poll such passive data sources, and trigger execution of tasks within the on-demand code execution system 110 based on the data provided. While depicted in FIG. 1 as distinct from the user computing devices 102 and the on-demand code execution system 110, in some embodiments, various auxiliary services 106 may be implemented by either the user computing devices 102 or the on-demand code execution system 110.

The illustrative environment 100 further includes one or more network-based data storage services 108, configured to enable the on-demand code execution system 110 to store and retrieve data from one or more persistent or substantially persistent data sources. Illustratively, the network-based data storage services 108 may enable the on-demand code execution system 110 to store information corresponding to a task, such as code or metadata, to store additional code objects representing dependencies of tasks, to retrieve data to be processed during execution of a task, and to store information (e.g., results) regarding that execution. The network-based data storage services 108 may represent, for example, a relational or non-relational database. In another example, the network-based data storage services 108 may represent a network-attached storage (NAS), configured to provide access to data arranged as a file system. The network-based data storage services 108 may further enable the on-demand code execution system 110 to query for and retrieve information regarding data stored within the on-demand code execution system 110, such as by querying for a number of relevant files or records, sizes of those files or records, file or record names, file or record creation times, etc. In some instances, the network-based data storage services 108 may provide additional functionality, such as the ability to separate data into logical groups (e.g., groups associated with individual accounts, etc.). While shown as distinct from the auxiliary services 106, the network-based data storage services 108 may in some instances also represent a type of auxiliary service 106.

The user computing devices 102, auxiliary services 106, and network-based data storage services 108 may communicate with the on-demand code execution system 110 via a network 104, which may include any wired network, wireless network, or combination thereof. For example, the network 104 may be a personal area network, local area network, wide area network, over-the-air broadcast network (e.g., for radio or television), cable network, satellite network, cellular telephone network, or combination thereof. As a further example, the network 104 may be a publicly accessible network of linked networks, possibly operated by various distinct parties, such as the Internet. In some embodiments, the network 104 may be a private or semi-private network, such as a corporate or university intranet. The network 104 may include one or more wireless networks, such as a Global System for Mobile Communications (GSM) network, a Code Division Multiple Access (CDMA) network, a Long Term Evolution (LTE) network, or any other type of wireless network. The network 104 can use protocols and components for communicating via the Internet or any of the other aforementioned types of networks. For example, the protocols used by the network 104 may include Hypertext Transfer Protocol (HTTP), HTTP Secure (HTTPS), Message Queue Telemetry Transport (MQTT), Constrained Application Protocol (CoAP), and the like. Protocols and components for communicating via the Internet or any of the other aforementioned types of communication networks are well known to those skilled in the art and, thus, are not described in more detail herein.

The on-demand code execution system 110 is depicted in FIG. 1 as operating in a distributed computing environment including several computer systems that are interconnected using one or more computer networks (not shown in FIG. 1). The on-demand code execution system 110 could also operate within a computing environment having a fewer or greater number of devices than are illustrated in FIG. 1. Thus, the depiction of the on-demand code execution system 110 in FIG. 1 should be taken as illustrative and not limiting to the present disclosure. For example, the on-demand code execution system 110 or various constituents thereof could implement various Web services components, hosted or “cloud” computing environments, and/or peer to peer network configurations to implement at least a portion of the processes described herein.

Further, the on-demand code execution system 110 may be implemented directly in hardware or software executed by hardware devices and may, for instance, include one or more physical or virtual servers implemented on physical computer hardware configured to execute computer executable instructions for performing various features that will be described herein. The one or more servers may be geographically dispersed or geographically co-located, for instance, in one or more data centers. In some instances, the one or more servers may operate as part of a system of rapidly provisioned and released computing resources, often referred to as a “cloud computing environment.”

In the example of FIG. 1, the on-demand code execution system 110 is illustrated as connected to the network 104. In some embodiments, any of the components within the on-demand code execution system 110 can communicate with other components of the on-demand code execution system 110 via the network 104. In other embodiments, not all components of the on-demand code execution system 110 are capable of communicating with other components of the virtual environment 100. In one example, only the frontend 120 (which may in some instances represent multiple frontends 120) may be connected to the network 104, and other components of the on-demand code execution system 110 may communicate with other components of the environment 100 via the frontends 120.

In FIG. 1, users, by way of user computing devices 102, may interact with the on-demand code execution system 110 to provide executable code, and establish rules or logic defining when and how such code should be executed on the on-demand code execution system 110, thus establishing a “task.” For example, a user may wish to run a piece of code in connection with a web or mobile application that the user has developed. One way of running the code would be to acquire virtual machine instances from service providers who provide infrastructure as a service, configure the virtual machine instances to suit the user's needs, and use the configured virtual machine instances to run the code. In order to avoid the complexity of this process, the user may alternatively provide the code to the on-demand code execution system 110, and request that the on-demand code execution system 110 execute the code. The on-demand code execution system 110 can handle the acquisition and configuration of compute capacity (e.g., containers, instances, etc., which are described in greater detail below) based on the code execution request, and execute the code using the compute capacity. The on-demand code execution system 110 may automatically scale up and down based on the volume, thereby relieving the user from the burden of having to worry about over-utilization (e.g., acquiring too little computing resources and suffering performance issues) or under-utilization (e.g., acquiring more computing resources than necessary to run the codes, and thus overpaying). In accordance with embodiments of the present disclosure, and as described in more detail below, the on-demand code execution system 110 may configure the virtual machine instances with customized operating systems to execute the user's code more efficiency and reduce utilization of computing resources.

To enable interaction with the on-demand code execution system 110, the system 110 includes one or more frontends 120, which enable interaction with the on-demand code execution system 110. In an illustrative embodiment, the frontends 120 serve as a “front door” to the other services provided by the on-demand code execution system 110, enabling users (via user computing devices 102) to provide, request execution of, and view results of computer executable code. The frontends 120 include a variety of components to enable interaction between the on-demand code execution system 110 and other computing devices. For example, each frontend 120 may include a request interface providing user computing devices 102 with the ability to upload or otherwise communication user-specified code to the on-demand code execution system 110 and to thereafter request execution of that code. In one embodiment, the request interface communicates with external computing devices (e.g., user computing devices 102, auxiliary services 106, etc.) via a graphical user interface (GUI), CLI, or API. The frontends 120 process the requests and makes sure that the requests are properly authorized. For example, the frontends 120 may determine whether the user associated with the request is authorized to access the user code specified in the request.

References to user code as used herein may refer to any program code (e.g., a program, routine, subroutine, thread, etc.) written in a specific program language. In the present disclosure, the terms “code,” “user code,” and “program code,” may be used interchangeably. Such user code may be executed to achieve a specific function, for example, in connection with a particular web application or mobile application developed by the user. As noted above, individual collections of user code (e.g., to achieve a specific function) are referred to herein as “tasks,” while specific executions of that code (including, e.g., compiling code, interpreting code, or otherwise making the code executable) are referred to as “task executions” or simply “executions.” Tasks may be written, by way of non-limiting example, in JavaScript (e.g., node.js), Java, Python, and/or Ruby (and/or another programming language). Tasks may be “triggered” for execution on the on-demand code execution system 110 in a variety of manners. In one embodiment, a user or other computing device may transmit a request to execute a task may, which can generally be referred to as “call” to execute of the task. Such calls may include the user code (or the location thereof) to be executed and one or more arguments to be used for executing the user code. For example, a call may provide the user code of a task along with the request to execute the task. In another example, a call may identify a previously uploaded task by its name or an identifier. In yet another example, code corresponding to a task may be included in a call for the task, as well as being uploaded in a separate location (e.g., storage of an auxiliary service 106 or a storage system internal to the on-demand code execution system 110) prior to the request being received by the on-demand code execution system 110. As noted above, the code for a task may reference additional code objects maintained at the on-demand code execution system 110 by use of identifiers of those code objects, such that the code objects are combined with the code of a task in an execution environment prior to execution of the task. The on-demand code execution system 110 may vary its execution strategy for a task based on where the code of the task is available at the time a call for the task is processed. A request interface of the frontend 120 may receive calls to execute tasks as Hypertext Transfer Protocol Secure (HTTPS) requests from a user. Also, any information (e.g., headers and parameters) included in the HTTPS request may also be processed and utilized when executing a task. As discussed above, any other protocols, including, for example, HTTP, MQTT, and CoAP, may be used to transfer the message containing a task call to the request interface 122.

A call to execute a task may specify one or more third-party libraries (including native libraries) to be used along with the user code corresponding to the task. In one embodiment, the call may provide to the on-demand code execution system 110 a file containing the user code and any libraries (and/or identifications of storage locations thereof) corresponding to the task requested for execution. In some embodiments, the call includes metadata that indicates the program code of the task to be executed, the language in which the program code is written, the user associated with the call, and/or the computing resources (e.g., memory, etc.) to be reserved for executing the program code. For example, the program code of a task may be provided with the call, previously uploaded by the user, provided by the on-demand code execution system 110 (e.g., standard routines), and/or provided by third parties. Illustratively, code not included within a call or previously uploaded by the user may be referenced within metadata of the task by use of a URI associated with the code. In some embodiments, such resource-level constraints (e.g., how much memory is to be allocated for executing a particular user code) are specified for the particular task, and may not vary over each execution of the task. In such cases, the on-demand code execution system 110 may have access to such resource-level constraints before each individual call is received, and the individual call may not specify such resource-level constraints. In some embodiments, the call may specify other constraints such as permission data that indicates what kind of permissions or authorities that the call invokes to execute the task. Such permission data may be used by the on-demand code execution system 110 to access private resources (e.g., on a private network). In some embodiments, individual code objects may also be associated with permissions or authorizations. For example, a third party may submit a code object and designate the object as readable by only a subset of users. The on-demand code execution system 110 may include functionality to enforce these permissions or authorizations with respect to code objects.

In some embodiments, a call may specify the behavior that should be adopted for handling the call. In such embodiments, the call may include an indicator for enabling one or more execution modes in which to execute the task referenced in the call. For example, the call may include a flag or a header for indicating whether the task should be executed in a debug mode in which the debugging and/or logging output that may be generated in connection with the execution of the task is provided back to the user (e.g., via a console user interface). In such an example, the on-demand code execution system 110 may inspect the call and look for the flag or the header, and if it is present, the on-demand code execution system 110 may modify the behavior (e.g., logging facilities) of the container in which the task is executed, and cause the output data to be provided back to the user. In some embodiments, the behavior/mode indicators are added to the call by the user interface provided to the user by the on-demand code execution system 110. Other features such as source code profiling, remote debugging, etc. may also be enabled or disabled based on the indication provided in a call.

To manage requests for code execution, the frontend 120 can include an execution queue (not shown in FIG. 1), which can maintain a record of requested task executions. Illustratively, the number of simultaneous task executions by the on-demand code execution system 110 is limited, and as such, new task executions initiated at the on-demand code execution system 110 (e.g., via an API call, via a call from an executed or executing task, etc.) may be placed on the execution queue 124 and processed, e.g., in a first-in-first-out order. In some embodiments, the on-demand code execution system 110 may include multiple execution queues, such as individual execution queues for each user account. For example, users of the on-demand code execution system 110 may desire to limit the rate of task executions on the on-demand code execution system 110 (e.g., for cost reasons). Thus, the on-demand code execution system 110 may utilize an account-specific execution queue to throttle the rate of simultaneous task executions by a specific user account. In some instances, the on-demand code execution system 110 may prioritize task executions, such that task executions of specific accounts or of specified priorities bypass or are prioritized within the execution queue. In other instances, the on-demand code execution system 110 may execute tasks immediately or substantially immediately after receiving a call for that task, and thus, the execution queue may be omitted.

As noted above, tasks may be triggered for execution at the on-demand code execution system 110 based on explicit calls from user computing devices 102 (e.g., as received at the request interface). Alternatively or additionally, tasks may be triggered for execution at the on-demand code execution system 110 based on data retrieved from one or more auxiliary services 106 or network-based data storage services 108. To facilitate interaction with auxiliary services 106, the frontend 120 can include a polling interface (not shown in FIG. 1), which operates to poll auxiliary services 106 or data storage services 108 for data. Illustratively, the polling interface may periodically transmit a request to one or more user-specified auxiliary services 106 or data storage services 108 to retrieve any newly available data (e.g., social network “posts,” news articles, files, records, etc.), and to determine whether that data corresponds to a user-established criteria triggering execution a task on the on-demand code execution system 110. Illustratively, criteria for execution of a task may include, but is not limited to, whether new data is available at the auxiliary services 106 or data storage services 108, the type or content of the data, or timing information corresponding to the data. In some instances, the auxiliary services 106 or data storage services 108 may function to notify the frontend 120 of the availability of new data, and thus the polling service may be unnecessary with respect to such services.

In addition to tasks executed based on explicit user calls and data from auxiliary services 106, the on-demand code execution system 110 may in some instances operate to trigger execution of tasks independently. For example, the on-demand code execution system 110 may operate (based on instructions from a user) to trigger execution of a task at each of a number of specified time intervals (e.g., every 10 minutes).

The frontend 120 can further include an output interface (not shown in FIG. 1) configured to output information regarding the execution of tasks on the on-demand code execution system 110. Illustratively, the output interface may transmit data regarding task executions (e.g., results of a task, errors related to the task execution, or details of the task execution, such as total time required to complete the execution, total data processed via the execution, etc.) to the user computing devices 102 or to auxiliary services 106, which may include, for example, billing or logging services. The output interface may further enable transmission of data, such as service calls, to auxiliary services 106. For example, the output interface may be utilized during execution of a task to transmit an API request to an external service 106 (e.g., to store data generated during execution of the task).

In some embodiments, the on-demand code execution system 110 may include multiple frontends 120. In such embodiments, a load balancer (not shown in FIG. 1) may be provided to distribute the incoming calls to the multiple frontends 120, for example, in a round-robin fashion. In some embodiments, the manner in which the load balancer distributes incoming calls to the multiple frontends 120 may be based on the location or state of other components of the on-demand code execution system 110. For example, a load balancer may distribute calls to a geographically nearby frontend 120, or to a frontend with capacity to service the call. In instances where each frontend 120 corresponds to an individual instance of another component of the on-demand code execution system, such as the active pool 140A described below, the load balancer may distribute calls according to the capacities or loads on those other components. As will be described in more detail below, calls may in some instances be distributed between frontends 120 deterministically, such that a given call to execute a task will always (or almost always) be routed to the same frontend 120. This may, for example, assist in maintaining an accurate execution record for a task, to ensure that the task executes only a desired number of times. While distribution of calls via a load balancer is illustratively described, other distribution techniques, such as anycast routing, will be apparent to those of skill in the art.

To execute tasks, the on-demand code execution system 110 includes one or more preconfigured OS libraries 130, which in turn include one or more preconfigured operating system variants. In the example illustrated in FIG. 1, the preconfigured OS library 130 includes a preconfigured OS 132, which comprises a kernel 132A and a module 132B, and a preconfigured OS 134, which comprises a kernel 134A. In some embodiments, as described in more detail below, the kernel 132A and the kernel 134A may be the same, and the difference between the preconfigured OS 132 and the preconfigured OS 134 may be the presence or absence of the module 132B. In other embodiments, the different preconfigured OSes 132 and 134 may have different kernels 132A and 134A. For example, the kernel 134A may contain a subset of the operating system functions implemented by the kernel 132A, or the kernels 132A and 134A may each provide distinct functionality. In other embodiments, the preconfigured OS libraries 130 may contain kernel modules or other “building blocks” for assembling an operating system, rather than containing a library of preconfigured OSes. Preconfigured OS 132 and preconfigured OS 134 may, in some embodiments, be variants of the same operating system, and may differ in terms of the functionality that is incorporated into the kernels 132A and 134A at the operating system level (“kernel-space functionality”), as opposed to functionality that is provided or incorporated at the user level such as applications, runtimes, user preferences, non-native libraries, and the like.

The preconfigured OS libraries 130 support rapid provisioning and configuration of virtual machine instances, such as the virtual machine instances 150 and 152. In one embodiments, the preconfigured OSes in a particular library 130 may be preconfigured in the same or substantially similar manner. For example, the preconfigured OSes may be variants of a particular operating system with particular kernel subsystems or modules included or excluded, particular OS libraries included or excluded, particular device drivers included or excluded, and so forth. As another example, the preconfigured OSes in a particular library 130 may all omit a particular set of operating system functions, such as filesystem APIs or networking APIs. In some embodiments, each preconfigured OS library 130 may be associated with a particular worker manager 140, which may manage resources that correspond to the library 130's preconfigured OSes. For example, a particular worker manager 140 may be provisioned without access to storage media, and may be associated with a preconfigured OS library 130 of operating systems that do not provide filesystem functions.

The on-demand code execution system 110 further includes an OS configuration system 160, which implements aspects of the present disclosure including, for example, the generation or selection of a customized OS variant for a particular task. In some embodiments, the OS configuration system 160 includes a static runtime analyzer 162, which may be invoked when the user submits code via the frontend 120 to determine an OS variant to use with the submitted code. As described in more detail below, the static runtime analyzer 162 may analyze the user's code and identify, for example, API calls, operating system calls, function calls, or other indications of OS functionality that the code will require during execution. In various embodiments, the static runtime analyzer 162 may analyze keywords, symbols, headers, directives, or other aspects of the user's code. In further embodiments, the on-demand code execution system 110 includes a dynamic runtime analyzer 164, which may be invoked when the user's code it executed to analyze the OS functionality that is actually utilized during execution of the code. The dynamic runtime analyzer 164 may identify, for example, a portion of the source code that requires specific OS functionality, but is seldom or never reached during execution. For example, the user's code may write to a log file if it encounters a particular error condition, but the error may be relatively infrequent (e.g., the user's code may frequently run to completion without encountering the error condition) and the code may otherwise not perform any filesystem reads or writes.

In accordance with aspects of the present disclosure, the OS configuration system 160 further includes a provisioning unit 166 configured to provision a customized OS with the functionality identified by the static runtime analyzer 162, the dynamic runtime analyzer 164, or both. Specifically, and as discussed in more detail below, the provisioning unit 166 may provision a preconfigured OS from the preconfigured OS library 130, or may generate instructions or other configuration information for selecting, generating, or provisioning an OS. The configuration information may be stored (e.g., in the data storage service 108) for later use by the worker manager 140 when a subsequent code execution is requested. The provisioning unit 166 can accordingly operate to improve operation of the system 110 as a whole during provisioning of virtual machine instances by removing unused code from the operating system and reducing the overhead requirements of the instances.

The on-demand code execution system further includes one or more worker managers 140 that manage the instances used for servicing incoming calls to execute tasks. In the example illustrated in FIG. 1, each worker manager 140 manages an active pool 140A, which is a group (sometimes referred to as a pool) of virtual machine instances, implemented by one or more physical host computing devices, that are currently assigned to one or more users. Although the virtual machine instances are described here as being assigned to a particular user, in some embodiments, the instances may be assigned to a group of users, such that the instance is tied to the group of users and any member of the group can utilize resources on the instance. For example, the users in the same group may belong to the same security group (e.g., based on their security credentials) such that executing one member's task in a container on a particular instance after another member's task has been executed in another container on the same instance does not pose security risks. Similarly, the worker managers 140 may assign the instances and the containers according to one or more policies that dictate which requests can be executed in which containers and which instances can be assigned to which users. An example policy may specify that instances are assigned to collections of users who share the same account (e.g., account for accessing the services provided by the on-demand code execution system 110). In some embodiments, the requests associated with the same user group may share the same containers (e.g., if the user codes associated therewith are identical). In some embodiments, a task does not differentiate between the different users of the group and simply indicates the group to which the users associated with the task belong.

Once a triggering event to execute a task has been successfully processed by a frontend 120, the frontend 120 passes a request to a worker manager 140 to execute the task. In one embodiment, each frontend 120 may be associated with a corresponding worker manager 140 (e.g., a worker manager 140 co-located or geographically nearby to the frontend 120) and thus, the frontend 120 may pass most or all requests to that worker manager 140. In another embodiment, a frontend 120 may include a location selector configured to determine a worker manager 140 to which to pass the execution request. In one embodiment, the location selector may determine the worker manager 140 to receive a call based on hashing the call, and distributing the call to a worker manager 140 selected based on the hashed value (e.g., via a hash ring). Various other mechanisms for distributing calls between worker managers 140 will be apparent to one of skill in the art. In accordance with embodiments of the present disclosure, the worker manager 140 can obtain an OS configuration and/or a preconfigured OS when provisioning a virtual machine instance.

As shown in FIG. 1, instances may have operating systems (OS), language runtimes, and containers. The containers may have individual copies of the OS, the runtimes, and user codes corresponding to various tasks loaded thereon. In the example of FIG. 1, the active pools 140A managed by a worker manager 140 includes the instances 150 and 152. The instance 150 has a preconfigured OS 150A, runtimes 150B and 150C, and containers 150D and 150E. The container 150D includes a copy of the runtime 150B, and a copy of a code 150D-1. The container 150E includes a copy of the runtime 150C, and a copy of a code 150E-1. The instance 152 has a preconfigured OS 152A, runtimes 152B, 152C, 152E, and 152F, a container 152D, and codes 152G and 152H. The container 152D has a copy of the runtime 152B and a copy of a code 152D-1. As illustrated in FIG. 1, instances may have user codes loaded thereon, and containers within those instances may also have user codes loaded therein. In some embodiments, the runtimes may also be user provided. Illustrative examples for utilization of user-provided runtimes on the on-demand code execution system are described in U.S. patent application Ser. No. 15/841,132, entitled “MANAGING CUSTOM RUNTIMES IN AN ON-DEMAND CODE EXECUTION SYSTEM,” and filed Dec. 13, 2017 (the “'132 application”), the entirety of which is hereby incorporated by reference. In some embodiments, the worker managers 140 may maintain a list of instances in an active pool 140A. The list of instances may further specify the configuration (e.g., OS, runtime, container, etc.) of the instances. In some embodiments, the worker managers 140 may have access to a list of instances in a warming pool (e.g., including the number and type of instances). In other embodiments, the worker managers 140 requests compute capacity from a warming pool manager without having knowledge of the virtual machine instances in a warming pool.

In the example illustrated in FIG. 1, tasks are executed in isolated execution environments referred to as containers (e.g., containers 150D, 150E, 152D). Containers are logical units created within a virtual machine instance using the resources available on that instance. For example, each worker manager 140 may, based on information specified in a call to execute a task, create a new container or locate an existing container in one of the instances in an active pool 140A and assigns the container to the call to handle the execution of the task.

While some functionalities are generally described herein with reference to an individual component of the on-demand code execution system 110, other components or a combination of components may additionally or alternatively implement such functionalities. For example, a worker manager 140 may operate to select preconfigured OSes or generate OSes in a manner similar or identical to as described herein with reference to an OS configuration system 160.

FIG. 2 depicts a general architecture of a computing system (referenced as OS configuration system 160) that operates to determine OS variants within the on-demand code execution system 110. The general architecture of the OS configuration system 160 depicted in FIG. 2 includes an arrangement of computer hardware and software modules that may be used to implement aspects of the present disclosure. The hardware modules may be implemented with physical electronic devices, as discussed in greater detail below. The OS configuration system 160 may include many more (or fewer) elements than those shown in FIG. 2. It is not necessary, however, that all of these generally conventional elements be shown in order to provide an enabling disclosure. Additionally, the general architecture illustrated in FIG. 2 may be used to implement one or more of the other components illustrated in FIG. 1. As illustrated, the OS configuration system 160 includes a processing unit 290, a network interface 292, a computer readable medium drive 294, and an input/output device interface 296, all of which may communicate with one another by way of a communication bus. The network interface 292 may provide connectivity to one or more networks or computing systems. The processing unit 290 may thus receive information and instructions from other computing systems or services via the network 104. The processing unit 290 may also communicate to and from memory 280 and further provide output information for an optional display (not shown) via the input/output device interface 296. The input/output device interface 296 may also accept input from an optional input device (not shown).

The memory 280 may contain computer program instructions (grouped as modules in some embodiments) that the processing unit 290 executes in order to implement one or more aspects of the present disclosure. The memory 280 generally includes random access memory (RAM), read only memory (ROM) and/or other persistent, auxiliary or non-transitory computer readable media. The memory 280 may store an operating system 284 that provides computer program instructions for use by the processing unit 290 in the general administration and operation of the OS configuration system 160. The memory 280 may further include computer program instructions and other information for implementing aspects of the present disclosure. For example, in one embodiment, the memory 280 includes a user interface unit 282 that generates user interfaces (and/or instructions therefor) for display upon a computing device, e.g., via a navigation and/or browsing interface such as a browser or application installed on the computing device. In addition, the memory 280 may include and/or communicate with one or more data repositories (not shown), for example, to access user program codes and/or libraries.

In addition to and/or in combination with the user interface unit 282, the memory 280 may include a static runtime analyzer 162, a dynamic runtime analyzer 164, and a provisioning unit 166 that may be executed by the processing unit 290. In one embodiment, the static runtime analyzer 162, dynamic runtime analyzer 164, and provisioning unit 166 individually or collectively implement various aspects of the present disclosure, e.g., generating or selecting customized operating system variants within the on-demand code execution system 110, analyzing code or code execution to determine required OS functionality, etc., as described further below.

While the static runtime analyzer 162, dynamic runtime analyzer 164, and provisioning unit 166 are shown in FIG. 2 as part of the OS configuration system 160, in other embodiments, all or a portion of the static runtime analyzer 162, dynamic runtime analyzer 164, and provisioning unit 166 may be implemented by other components of the on-demand code execution system 110 and/or another computing device. For example, in certain embodiments of the present disclosure, another computing device in communication with the on-demand code execution system 110 may include several modules or components that operate similarly to the modules and components illustrated as part of the OS configuration system 160.

In some embodiments, the OS configuration system 160 may further include components other than those illustrated in FIG. 2. For example, the memory 280 may further include an instance allocation unit for allocating execution environments to tasks, user code execution unit to facilitate execution of tasks within the execution environments, or a container manager for managing creation, preparation, and configuration of containers within virtual machine instances.

With reference to FIG. 3, illustrative interactions are depicted for determination of OS variants. The interactions of FIG. 3 begin at (1), where a user device 102 may generate task code for execution on an on-demand code execution system 110. Illustratively, the user may generate code that makes various system calls, and thus requires an operating system that provides corresponding functionality. At (2), the user device 102 submits the task code to the frontend 120, such as by using a API or other interface of the frontend 120, and at (3) the frontend 120 validates the submitted task code. Validation can include, for example, verifying that the task code can be executed by the on-demand code execution system 110.

At (4), the frontend 120 transmits a request to the OS configuration system 160 to generate or select an OS variant for the task. The OS configuration system 160, in turn, analyzes the task code at (5) to determine a suitable OS variant. Illustratively, the static runtime analyzer 162 of the OS configuration system may identify a programming language or languages in which the task code is written, such as Perl, Ruby, Python, JavaScript, Java, or the like. The static runtime analyzer 162 may further identify language keywords associated with operating system functions. For example, the static runtime analyzer 162 may determine that a task written in Java imports the java.io.file package, and thus may require an OS that includes filesystem functionality. The static runtime analyzer 162 may further analyze the task code to identify specific keywords or operations associated with particular functionality. For example, the static runtime analyzer 162 may determine that the task code requires an OS that facilitates reading UDP datagrams from a networked data stream, but does not require that the OS facilitate writing to the data stream, buffering the data stream, network protocols other than UDP, or other networking functionality.

In some embodiments, the OS configuration system 160 may determine an OS variant for the task by selecting a preconfigured OS from a library, such as the preconfigured OS library 130 of FIG. 1. For example, the OS configuration system 160 may identify OS functionality that the task code requires, and may identify one or more preconfigured OSes that provide this functionality. In some embodiments, the OS configuration system 160 may select an OS variant from among a number of preconfigured OSes that provide the required functionality based on criteria such as resource requirements, load times, response times, or other criteria that compare or rank the eligible OSes. In further embodiments, the preconfigured OS library 130 may store rankings or ratings with the preconfigured OSes, and the OS configuration system 160 may select a preconfigured OS that provides the needed functionality based on the rankings or ratings.

As an example, the OS configuration system 160 may determine that the task code for a particular task can execute to completion without exhausting the physical memory that is allocated to a virtual machine instance. Accordingly, the OS configuration system 160 can determine that the virtual machine instance's OS variant does not need to implement memory management functions such as swapping, paging, address translation, and so forth, since these functions will not be needed within the lifecycle of the virtual machine instance. The OS configuration system 160 may thus obtain a preconfigured OS variant that does not implement these functions, and that does implement functions required by the task code (e.g., functions relating to threading and inter-process communication).

In some embodiments, the OS configuration system 160 may generate an OS variant that provides the specific functionality required by the task. For example, the OS configuration system may identify a set of loadable kernel modules, userspace processes, or other components that provide the required functionality, and may generate an OS variant that includes those specific components. In some embodiments, the OS configuration system 160 may implement or utilize a microkernel architecture to generate custom OS variants. In other embodiments, the OS configuration system 160 may utilize a library of preconfigured OS variants with differing monolithic kernels as described above.

At (6), the OS configuration system 160 may store information identifying the determined OS variant, and in some embodiments the validated task code, in a storage device such as the data storage device 108. The on-demand code execution system 110 may thus reduce the time spent analyzing code and determining OS variants when receiving a request to execute the task code, as discussed in more detail below.

In some embodiments, the ordering and implementation of operations described above may be modified, or these interactions may be carried out by additional or alternative elements of the on-demand code execution system 110. For example, in one embodiment, the frontend 120 may enable user selection of a preconfigured OS from the library 130 (or from a subset of available OSes in the library 130), and the OS configuration system 160 may analyze the task code to identify and report any issues that would prevent the task code from executing with the user-selected OS variant. As a further example, in another embodiment, the OS configuration system 160 may identify an OS variant from among a set of OS variants that are currently in use in the active pool 140A of FIG. 1. Still further, in another embodiment, worker managers 140 may be categorized according to the OS variant(s) that they execute, and the OS configuration system 160 may select an OS variant by designating the worker manager(s) 140 upon which the task code may be executed.

Illustrative interactions for utilizing the determined OS variant to execute tasks on the on-demand code execution system 110 will be described with reference to FIG. 4. At (1), the user device 102 may request task execution. In some embodiments, as described above, the frontend 120 may initiate task execution without receiving a request, in which case the interaction at (1) may be omitted.

At (2), the frontend 120 distributes the task for execution to the worker manager 140. Prior to distributing the task execution, the frontend 120 may undertake any of a number of additional interactions, such as queuing the request, validating the request, etc., as described in more detail within the '556 patent, incorporated by reference above.

At (3), the worker manager 140 requests information identifying an OS variant for the task. In some embodiments, as described above, an OS variant may be determined when the code of the task is submitted for validation (e.g., by carrying out the interactions illustrated in FIG. 3). In other embodiments, as described below with reference to FIG. 5, the OS variant may be determined or updated based on an analysis or analyses of previous executions of the task. At (4), the worker manager 140 receives information identifying the previously determined OS variant from the data storage device 108. In some embodiments, the worker manager 140 may also request and receive the user-submitted code associated with the task. In other embodiments, the worker manager 140 may receive the user-submitted code from the frontend 120 when the task is distributed for execution.

Thereafter, at (5), the worker manager 140 requests a preconfigured OS from the preconfigured OS library 130 that corresponds to the determined OS variant. In some embodiments, as described above, the worker manager 140 may instead identify a virtual machine instance in its active pool that has the desired OS variant. In other embodiments, the worker manager 140 may request the generation of a customized OS, or may generate a customized OS by assembling components or modules. At (6), the worker manager 140 receives the requested OS. In some embodiments, the worker manager 140 may determine that it does not have sufficient resources to provision a virtual machine with the identified OS variant, or may determine at an earlier stage (e.g., prior to the interaction at (3)) that it does not have sufficient resources to execute the task regardless of the OS variant. For example, the worker manager 140 may manage a pool of resources that does not include data storage, and the identified OS variant may be one that provides filesystem functionality. In such embodiments, the worker manager 140 may request that the provisioning unit 166 of FIG. 1 (or another component of the on-demand code execution system 110) select an alternate worker manager 140 to execute the task. In other embodiments, the worker manager 140 may request that the provisioning unit 166 select an alternate worker manager 140 to execute the task whenever the worker manager 140 does not have a pre-instantiated virtual machine executing the identified OS variant. Such a configuration may, for example, reduce or eliminate the need for interactions (5) and (6), as many or all executions would be expected to be serviced by a worker manager 140 with a pre-instantiated virtual machine executing the identified OS variant. In still more embodiments, the generation of a virtual machine executing an OS variant on a worker manager 140 may be handled by the provisioning unit 166. Thus, for example, if the worker manager 140 determines that a pre-instantiated virtual machine executing the identified OS variant is not available to the worker manager 140, the worker manager 140 may request that the provisioning unit 166 generate such a virtual machine on a host device under control of the worker manager 140.

At (7), the worker manager 140 configures (and, in some embodiments, provisions) a virtual machine instance with the OS variant and the task code, and then executes the task. Execution of the task may include, for example, locating and provisioning an execution environment, which is discussed in more detail within the '556 patent incorporated by reference.

In some embodiments, the ordering and implementation of operations described above may be modified, or these interactions may be carried out by additional or alternative elements of the on-demand code execution system. For example, in one embodiment, the frontend 120 may be configured to request an OS variant in accordance with interactions (3) and (4), above. These interactions may occur, for example, prior to a task execution being distributed to the worker manager 140. The worker manager 140 may then receive distribution of a task execution and an associated OS variant, and instruct the execution environment to execute the task. The environment, based on such instructions, may then implement interactions (4) and (5) to obtain a preconfigured OS from the library 130. Thereafter, the execution environment may execute code of the task, thus fulfilling the execution instructions of the frontend 120. Illustrative mechanisms for an environment to identify and retrieve code objects in order to execute a task are described in more detail within the '132 application, incorporated by reference above.

FIG. 5 depicts illustrative interactions for determining an OS variant based on an execution or executions of the task code. At (1), the worker manager 140 executes a task within a virtual machine instance. In some embodiments, the task may be executed on a virtual machine instance with an unconfigured OS, such as a standard or default OS. In other embodiments, the task may be executed on a virtual machine instance with an OS variant determined at the time the code was submitted (e.g., as described above with reference to FIG. 3), or with an OS variant that was previously determined by carrying out the interactions depicted in FIG. 5.

At (2), the OS configuration system 160 may monitor execution of the task within the virtual machine instance. Illustratively, the dynamic runtime analyzer 164 of the OS configuration system 160 may identify system calls made during execution of the task to determine the OS functionality that the task requires. For example, the dynamic runtime analyzer 164 may determine that execution(s) of the task have invoked OS functions relating to certain hardware device drivers, threading and process scheduling, and memory management, but not OS functions relating to networking or filesystems. Thereafter, at (3), the OS configuration system 160 may determine an OS variant. As described above, the OS configuration system 160 may determine an OS variant that minimizes the resource footprint of the OS while providing the functionality needed to execute the task.

In some embodiments, the OS configuration system 160 may determine a probability that the task will require a particular OS function or set of functions. For example, the OS configuration system 160 may monitor multiple executions of a particular task and determine that the task typically does not require networking functionality, but on rare occasions will require it. The OS configuration system 160 may thus perform a cost-benefit analysis to assess whether it is more efficient to execute the task with or without providing the functionality in the OS. For example, a resource cost (e.g., load time, memory footprint, latency, etc.) associated with providing the functionality may be determined. This resource cost may be compared to a resource cost associated with not providing the functionality, as well as a resource cost associated with recovering from a situation in which the functionality was needed but not provided. For example, the OS configuration system 160 may determine a cost associated with reloading and re-executing all or part of the task on a second virtual machine instance configured with an OS that provides the functionality. In some embodiments, state information, partial results, or other information may be transferred from one virtual machine instance to another in order to expedite recovery from a situation in which OS functionality was needed and not provided. In further embodiments, the OS configuration system 160 may determine an OS variant that does not provide the identified functionality and a “fallback” OS variant that does, and may store instructions for expediting recovery in the event the missing functionality is required. In still further embodiments, the OS configuration system 160 may determine that it would be faster (or otherwise more efficient) to re-execute the entire task on a virtual machine instance configured with a default, fully-featured OS than to attempt to salvage all or part of the attempt to execute the task on the virtual machine instance with the customized OS variant.

At (4), the OS configuration system 160 stores the determined OS variant(s) in a data store, such as the data storage service 108. In some embodiments, the OS configuration system 160 may determine whether a dynamic analysis of the task's OS requirements (e.g., an analysis performed on the executing task) is consistent with a previously performed static analysis (e.g., an analysis performed on the submitted task code), and may update its parameters for static analysis accordingly. For example, the OS configuration system 160 may determine a relationship between a particular element of the task code (e.g., a directive to import a particular module) and requiring certain OS functions, and may take this relationship into account when performing further static analyses. In some embodiments, the OS configuration system 160 may store a “recipe” or other instructions for building an OS variant from modules or other components. In other embodiments, the OS configuration system 160 may store information that identifies a preconfigured OS, information regarding the OS functionality required by the task code, or other information that enables the worker manager 140 to provision and configure a virtual machine instance with an OS that is customized for the task code the instance will execute.

An illustrative visualization of preconfigured operating systems is shown in FIG. 6. The illustrative visualization includes preconfigured OSes 132, 134, and 136, in which various functions that are provided by operating systems are represented as functional blocks or modules. In various embodiments, these blocks may represent modules or elements of an OS kernel, userspace processes or subsystems, libraries, drivers, or other elements of an operating system that can be functionally separated from each other.

In the visualization shown in FIG. 6, the preconfigured OS 132 is a “full” operating system that includes a full set OS functionality. The preconfigured OS 132 may correspond, for example, to a generally available OS (e.g., a standard Linux distro). In some embodiments, the preconfigured OS 132 may correspond to a custom OS that implements all of the functionality supported by an on-demand code execution system, but not all of the functionality supported by operating systems generally. For example, an on-demand code execution system may support only a simplified filesystem (e.g., a “flat” filesystem without directories), and so the preconfigured OS 132 may implement only a subset of filesystem-related system calls. In the illustrated embodiment, the preconfigured OS 132 includes a scheduler 632A, a memory management subsystem 632B, a filesystem management subsystem 632C, a networking subsystem 632D, and hardware device drivers 632E. One skilled in the art will appreciate that the list of components 632A-E is provided for purposes of example, and that the present disclosure includes embodiments in which operating systems have more, fewer, or different components than the ones depicted in FIG. 6. For example, the preconfigured OS 132 may include distinct modules for reading to filesystems and writing to filesystems, or different networking subsystems for different network protocols (e.g., a TCP/IP networking module and a UDP networking module).

The preconfigured OS 134 is a variant that implements a subset of the functionality provided by the preconfigured OS 132, including a scheduler 634A, a memory management subsystem 634B, and a networking subsystem 634D. The preconfigured OS 134 does not include functionality relating to filesystem management or hardware device drivers, and may thus be suitable only for tasks that do not require these functions. In some embodiments, the scheduler 634A may provide the same functionality as (or may be identical to) the scheduler 632A, or may provide different functionality. The preconfigured OS 136 further illustrates a minimal OS variant that provides only a scheduler 636A, and does not include any of the other functionality depicted in FIG. 6. In an embodiment, a preconfigured OS library, such as the preconfigured OS library 130 of FIG. 1, may include dozens or hundreds of other variations on preconfigured OSes 132, 134, and 136, including variations in which a scheduler is not provided. In another embodiment, all of the preconfigured OSes in a library may implement certain “core” OS functions such as task scheduling, and may vary in terms of other functions. In further embodiments, preconfigured OSes may vary in terms of the functionality implemented within one of the subsystems or modules depicted in FIG. 6. For example, a preconfigured OS may have more, fewer, or different hardware device drivers than another preconfigured OS, or may implement read-only networking.

In some embodiments, as described above, the OS configuration system 160 of FIG. 1 (or another component of the on-demand code execution system 110) may build an OS variant from individual modules or elements rather than selecting a preconfigured OS such as OS 134. For example, the OS configuration system 160 may determine that a particular task requires OS functions including task scheduling, memory management, and networking, and may thus assemble an OS out of individual components such as scheduler 632A, memory management subsystem 632B, networking subsystem 632D, and other such components. In further embodiments, the OS configuration system 160 may start with a base OS that includes minimal functionality and then add specific functions that the task may require. In other embodiments, the OS configuration system 160 may start with a fully-featured OS and remove functionality that the task may not require.

With reference to FIG. 7, one illustrative routine 700 for determining an OS variant for executing a task on the on-demand code execution system 110 will be described. The routine 700 may be carried out, for example, by the OS configuration system 160 of FIG. 1. In one embodiment, all or part of the routine 700 (e.g., blocks 702-706) is carried out in conjunction with the creation of a task on the on-demand code execution system 110. In another embodiment, all or part of the routine 700 (e.g., blocks 706-716) may be carried out in conjunction with executing the task on the on-demand code execution system 110. All or part of the routine 700 may additionally or alternatively be carried out at other times, such as periodically (e.g., once per day, week, month, etc.) or based on detection that execution metrics or resource utilization metrics fall outside a threshold.

The routine 700 begins at block 702, where the OS configuration system 160 obtains code for a task (e.g., as submitted by a user). In one embodiment, the code for the task is represented as a code object, such as a compressed file including source code for the task. The routine 700 then continues to blocks 704 and 706, where the OS configuration system 160 determines an OS variant for the task, shown in FIG. 7 as block collection 720.

At block 704, the OS configuration system 160 analyzes the obtained task code to identify OS functionality that may be required during code execution. Illustratively, the OS configuration system 160 may identify system calls, API calls, libraries, programming language features, or other indications that particular OS functionality may be required, as described in more detail above. In some embodiments, the OS configuration system 160 may compare the obtained task code to other task code executed by the on-demand code execution system 110, and may identify similarities or common features that identify required OS functionality. In other embodiments, the OS configuration system 160 may identify previous executions of the obtained task code and determine the OS functionality required during those executions. In various embodiments, the OS functionality may be identified as a particular set of functionality (e.g., networking functionality), as particular APIs or subsystems, or as individual functions or system calls.

At block 706, the OS configuration system 160 identifies a preconfigured OS that includes the functionality identified at block 704. In some embodiments, as described above, the OS configuration system 160 may identify multiple preconfigured OSes that include the identified functionality, and may apply various criteria (load times, execution speed, ratings or rankings of preconfigured OSes, etc.) to determine which of the preconfigured OSes to select. In other embodiments, the OS configuration system 160 may generate or assemble an OS with the required functionality, as described in more detail above. In some embodiments, the OS configuration system 160 may store the identified OS configuration and the task code in a data store for later use, and the portion of routine 700 after block 706 may be invoked as a separate routine when the task code is executed.

At block 708, the frontend 120 (or another element of the on-demand code execution system 110) receives a request to execute the task code. In one embodiment, the on-demand code execution system 110 may execute the task code without a request. For example, the on-demand code execution system 110 may execute the task code periodically, as described above, or may execute the task code when certain criteria are satisfied.

At block 710, the worker manager 140 or another component provisions a virtual machine instance with the identified preconfigured OS and the task code. In various embodiments, the worker manager 140 may select an existing virtual machine instance that is already provisioned with the preconfigured OS (including, for example, a virtual machine instance in a warming pool or other standby mode, as described in the '556 patent that is incorporated by reference above), build a custom OS from components, or otherwise provision the virtual machine with an OS variant that provides the functionality that the task code may require. In other embodiments, worker managers 140 may be associated with particular OS variant or variants, and the frontend 120 or another component may select a particular worker manager 140 based on the OS variant(s) supported by that worker manager 140.

At block 712, the worker manager 140 executes the task code. At block 714, the OS configuration system 160 may analyze the execution of the task code to identify OS functionality required during the execution. The OS configuration system 160 may analyze, for example, log files, network activity, filesystem activity, or other information generated or collected during execution of the task code. The analysis at block 714 is similar in purpose to the analysis carried out at block 704, but analyzes the functionality that is actually invoked during execution rather than analyzing the code to determine what functionality it may invoke. The analysis at block 714 may therefore identify portions of the task code that require specific OS functionality, but are seldom or never invoked during execution. For example, a subroutine in the code may require that the OS provide a particular device driver, but the code may not reach the subroutine during the execution at block 712. In some embodiments, the OS configuration system 160 may analyze several executions of the task code, as described above, to determine a probability that particular OS functions will be required during execution.

At decision block 716, the OS configuration system 160 may determine whether there is a mismatch between the functionality required by the task code and the functionality provided by the identified OS variant. It will be understood that the mismatch may be in either direction. For example, the OS configuration system 160 may determine that the identified OS variant provides more functionality than is needed to execute the task, and thus further efficiency gains may be realized by identifying a different OS variant. Alternatively, the OS configuration system 160 may determine that the identified OS variant does not provide all of the required functionality. For example, the OS configuration system 160 may determine that the worker manager 140 had to restart execution of the task code with a different OS variant than the one initially identified. In some embodiments, an OS variant may generate a “kernel panic” or other indication that required functionality is missing in order to cause the worker manager 140 to correct this situation. If the determination at decision block 716 is that a different OS variant is needed, then the routine 700 branches to block 706 and identifies the new OS variant. If not, the routine 700 branches to block 708 and awaits the next request to execute the task code, which will be fulfilled with the current OS variant.

The blocks of the routines described above may vary in embodiments of the present disclosure. For example, in some implementations of either routine, the OS configuration system 160 may be configured to implement additional functionality, such as generating and storing additional OS variants. Thus, the routines may include additional blocks, or the blocks of the routines may be rearranged, according to various embodiments.

All of the methods and processes described above may be embodied in, and fully automated via, software code modules executed by one or more computers or processors. The code modules may be stored in any type of non-transitory computer-readable medium or other computer storage device. Some or all of the methods may alternatively be embodied in specialized computer hardware.

Conditional language such as, among others, “can,” “could,” “might” or “may,” unless specifically stated otherwise, are otherwise understood within the context as used in general to present that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment.

Disjunctive language such as the phrase “at least one of X, Y or Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y or Z, or any combination thereof (e.g., X, Y and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain embodiments require at least one of X, at least one of Y or at least one of Z to each be present.

Unless otherwise explicitly stated, articles such as ‘a’ or ‘an’ should generally be interpreted to include one or more described items. Accordingly, phrases such as “a device configured to” are intended to include one or more recited devices. Such one or more recited devices can also be collectively configured to carry out the stated recitations. For example, “a processor configured to carry out recitations A, B and C” can include a first processor configured to carry out recitation A working in conjunction with a second processor configured to carry out recitations B and C.

Any routine descriptions, elements or blocks in the flow diagrams described herein and/or depicted in the attached figures should be understood as potentially representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or elements in the routine. Alternate implementations are included within the scope of the embodiments described herein in which elements or functions may be deleted, or executed out of order from that shown or discussed, including substantially synchronously or in reverse order, depending on the functionality involved as would be understood by those skilled in the art.

It should be emphasized that many variations and modifications may be made to the above-described embodiments, the elements of which are to be understood as being among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. 

What is claimed is:
 1. A system comprising: a physical data store storing a plurality of operating system (“OS”) variants, wherein individual OS variants of the plurality of OS variants provide respective sets of OS functions; and a computing device configured with executable instructions to: receive user-submitted code executable on an on-demand code execution system; determine a first set of OS functions that the user-submitted code is expected to invoke when executed on the on-demand code execution system; identify a first OS variant of the plurality of OS variants, wherein the first OS configuration provides at least the first set of OS functions; and in response to a request to execute the user-submitted code: provision a virtual machine instance with the first OS variant and the user-submitted code.
 2. The system of claim 1, wherein the computing device is further configured to identify one or more system calls in the user-submitted code, and wherein the first set of OS functions is determined based at least in part on the one or more system calls.
 3. The system of claim 1, wherein the first set of OS functions includes one or more of paging functions, caching functions, filesystem functions, networking functions, threading functions, profiling functions, scheduling functions, one or more networking protocol implementations, or one or more hardware device drivers.
 4. The system of claim 1, wherein the computing device is further configured to: identify a second OS variant of the plurality of OS variant, wherein the second OS variant provides at least the first set of OS functions; and determine that the first OS variant utilizes less of a first computing resource than the second OS variant.
 5. The system of claim 4, wherein the first computing resource comprises one or more of processing time, processor capacity, bandwidth, memory, storage, or latency.
 6. A computer-implemented method comprising: receiving user-submitted code executable on an on-demand code execution system; determining, based at least in part on the user-submitted code, a first set of OS functionality associated with executing the user-submitted code on the on-demand code execution system; identifying, based at least in part on the first set of OS functionality, a first OS variant of a plurality of OS variants; and in response to a request to execute the user-submitted code, executing the user-submitted code on a first virtual machine instance, the first virtual machine instance having the first OS variant.
 7. The computer-implemented method of claim 6 further comprising provisioning the first virtual machine instance with the first OS variant.
 8. The computer-implemented method of claim 6 further comprising selecting the first virtual machine instance having the first OS variant from a plurality of preconfigured virtual machine instances.
 9. The computer-implemented method of claim 6, wherein identifying the first OS variant is based at least in part on one or more previous executions of the user-submitted code.
 10. The computer-implemented method of claim 6, wherein a portion of the user-submitted code requires at least one function that is not provided by the first OS variant.
 11. The computer-implemented method of claim 10 further comprising determining, based at least in part on one or more previous executions of the user-submitted code, a probability that the portion of the user-submitted code that requires the at least one function will be executed.
 12. The computer-implemented method of claim 11 further comprising: obtaining a first resource cost associated with the first OS variant; and obtaining a second resource cost associated with a second OS variant, wherein the second OS variant provides the at least one function, wherein identifying the first OS variant is based at least in part on the first resource cost, the second resource cost, and the probability that the portion of the user-submitted code that requires the at least one function will be executed.
 13. The computer-implemented method of claim 10 further comprising: determining, during execution of the user-submitted code on the first virtual machine instance, that the execution of the user-submitted code requires the at least one function; and executing the user-submitted code on a second virtual machine instance having a second OS variant, wherein the second OS variant provides the at least one function.
 14. The computer-implemented method of claim 13, wherein the second OS variant corresponds to a default OS variant.
 15. The computer-implemented method of claim 13 further comprising transferring state information from the first virtual machine instance to the second virtual machine instance.
 16. Non-transitory computer-readable media including computer-executable instructions that, when executed on an on-demand code execution system, cause the on-demand code execution system to: obtain user-submitted code executable on an on-demand code execution system; determine, based at least in part on the user-submitted code, a first set of OS functionality associated with executing the user-submitted code; determine, based at least in part on the first set of OS functionality, a first OS variant; and in response to a request to execute the user-submitted code, execute the user-submitted code on a first virtual machine instance having the first OS variant.
 17. The non-transitory computer-readable media of claim 16 wherein the instructions further cause the on-demand code execution system to generate the first OS variant.
 18. The non-transitory computer-readable media of claim 17, wherein the first OS variant comprises a microkernel and one or more system processes.
 19. The non-transitory computer-readable media of claim 16, wherein the first OS variant is selected from a plurality of predefined OS configurations.
 20. The non-transitory computer-readable media of claim 16 wherein the instructions further cause the on-demand code execution system to execute the user-submitted code on a second virtual machine having the first OS variant in response to a second request to execute the user-submitted code. 